Engineering Commons^™

Monostatic Airborne Synthetic Aperture Radar Using Commercial Wimax Transceivers In The License-Exempt Spectrum, Kai Liu

Electronic Thesis and Dissertation Repository

The past half-century witnessed an evolution of synthetic aperture radar (SAR). Boosted by digital signal processing (DSP), a variety of SAR imaging algorithms have been developed, in which the wavenumber domain algorithm is mature for airborne SAR and independent of signal waveforms. Apart from the algorithm development, there is a growing interest in how to acquire the raw data of targets’ echoes before the DSP for SAR imaging in a cost-effective way. For the data acquisition, various studies over the past 15 years have shed light on utilizing the signal generated from the ubiquitous broadband wireless technology – orthogonal frequency …

Fault Location In Series Compensated Transmission Lines, Tirath Pal Singh Bains

Electronic Thesis and Dissertation Repository

Due to the integration of modern technology such as electric vehicles, the emphasis is expected to shift from mechanical to electric power. Therefore, the need of increasing the power transmission capacity of the electric grid gets highlighted. Since, the construction of transmission lines is a tedious task owing to legalities, environmental impacts and high costs, the series compensated transmission lines are gaining popularity due to lesser costs and faster construction time. The series capacitor compensated transmission lines are very crucial lines due to the greater power being transmitted through them. Therefore, an accurate fault location becomes a prerequisite for limiting …

A Phase-Angle Tracking Method For Synchronization Of Single- And Three-Phase Grid-Connected Converters, Farzam Baradarani

Electronic Thesis and Dissertation Repository

This thesis proposes a phase-angle tracking method, i.e., based on discrete Fourier transform for synchronization of three-phase and single-phase power-electronic converters under distorted and variable-frequency conditions. The proposed methods are designed based on fixed sampling rate and, thus, they can simply be employed for control applications. For three-phase applications, first, analytical analysis are presented to determine the errors associated with the phasor estimation using standard full-cycle discrete Fourier transform in a variable-frequency environment. Then, a robust phase-angle estimation technique is proposed, which is based on a combination of estimated positive and negative sequences, tracked frequency, and two proposed compensation coefficients. …

Automated Image Interpretation For Science Autonomy In Robotic Planetary Exploration, Raymond Francis

Electronic Thesis and Dissertation Repository

Advances in the capabilities of robotic planetary exploration missions have increased the wealth of scientific data they produce, presenting challenges for mission science and operations imposed by the limits of interplanetary radio communications. These data budget pressures can be relieved by increased robotic autonomy, both for onboard operations tasks and for decision- making in response to science data.

This thesis presents new techniques in automated image interpretation for natural scenes of relevance to planetary science and exploration, and elaborates autonomy scenarios under which they could be used to extend the reach and performance of exploration missions on planetary surfaces.

Two …

Estimation Of Hidden Markov Models And Their Applications In Finance, Anton Tenyakov

Electronic Thesis and Dissertation Repository

Movements of financial variables exhibit extreme fluctuations during periods of economic crisis and times of market uncertainty. They are also affected by institutional policies and intervention of regulatory authorities. These structural changes driving prices and other economic indicators can be captured reasonably by models featuring regime-switching capabilities. Hidden Markov models (HMM) modulating the model parameters to incorporate such regime-switching dynamics have been put forward in recent years, but many of them could still be further improved. In this research, we aim to address some of the inadequacies of previous regime-switching models in terms of their capacity to provide better forecasts …

Human Metaphase Chromosome Analysis Using Image Processing, Akila M.S Subasinghe Arachchige

Electronic Thesis and Dissertation Repository

Development of an effective human metaphase chromosome analysis algorithm can optimize expert time usage by increasing the efficiency of many clinical diagnosis processes. Although many methods exist in the literature, they are only applicable for limited morphological variations and are specific to the staining method used during cell preparation. They are also highly influenced by irregular chromosome boundaries as well as the presence of artifacts such as premature sister chromatid separation.

Therefore an algorithm is proposed in this research which can operate with any morphological variation of the chromosome across images from multiple staining methods. The proposed algorithm is capable …

An Accurate Offline Phasor Estimation Technique For Fault Location In Series Compensated Lines, Rubeena Rubeena

Electronic Thesis and Dissertation Repository

In series compensated transmission lines, current and voltage signals measured by the line protection system include considerable sub-synchronous frequency components (SSFCs) which are not sufficiently damped within a typical fault clearing time of line protection system. This does not allow accurate phasor estimation and thereby phasor-based fault location. This paper presents an accurate algorithm which effectively filters out the unwanted frequency components and noise to perform accurate phasor estimation for fault location in series compensated transmission lines. Phasor estimation of a theoretical signal is first evaluated using the proposed method, Direct-Prony analysis and 4-cycle discrete Fourier transform algorithm. Then, various …